REMOTE ENTRY NOT WORKING

Buick Regal

I have a 2000 Buick Regal LS. It has a remote entry with lock, unlock, trunk, and an alarm button. I have always used the remote to open the car and never the key. This morning, I was unable to open the car using the remote. I then tried opening the door with the key and that did not work. I wasn't able to unlock the trunk with the key either. The key and remote I have are the originals from the dealer for the car, and I have never had a problem opening or starting the car before. I also noticed that the CD that was in the CD player had been ejected. My first thought was that I needed to replace the battery in the key chain remote, but when I wasn't able to open any of the locks with the key and I saw the CD out, I thought maybe it was a bigger issue. Any ideas?